Question

Two particles are traveling in the x-y plane. Particle 1 is traveling in the positive x-direction with a1 = -6.25m/s2 i�. Particle 2 is initially 43m directly below Particle 1 (in the j� direction) and is traveling with an initial velocity of 35m/s and acceleration of 7.5m/s2, both directed at an angle of 25º above the positive x-axis. What initial velocity must particle 1 have in order to collide with particle 2?